1. Field of the Invention
The invention is based on a hydraulic assembly for a vehicle brake system with traction control.
2. Description of the Prior Art
Hydraulic assemblies for vehicle brake systems with traction control comprise a housing block and an electronic control unit. The housing block has many recesses for hydraulic components, such as solenoid valves, pumps or reservoirs. Connections for the wheel brakes of a vehicle brake system and for a master cylinder of a vehicle brake system are also embodied on the housing block. Bores in the interior of the housing block make hydraulic connections among these receptacles. The components are typically interconnected in two separate brake circuits. A housing block embodied in this way is known for instance from German Patent Disclosure DE 102 37 163 A1.
The aforementioned electronic control unit evaluates signals from sensors at the wheels of the vehicle, which each detect the prevailing slip conditions, and from sensors at the brake pedal of the master cylinder that detect its actuation and the scope of that actuation. In the control unit, the arriving signals are further processed into trigger signals. With these trigger signals, among other things the solenoid valves and the housing block are triggered, in order to regulate the brake pressure appropriately as a function of the particular slip conditions at the wheels of the vehicle.
It is moreover known to provide the housing block with a single pressure sensor. Typically, this pressure sensor detects the pressure at one of the connections with a master cylinder and thus furnishes the control unit with a further signal for controlling a vehicle brake system. In the brochure Fahrstabilisierungssysteme [Travel Stability Systems] in the Gelbe Reihe [Yellow Series] by Robert Bosch GmbH, 2004 Edition, page 90, FIG. 1, a hydraulic assembly sold on a large scale shown in an exploded view. This hydraulic assembly has a pressure sensor 9 that is disposed away from an imaginary center axis through the housing block.
It is disadvantageous that with a single pressure sensor, exact conclusions about the pressure conditions of all the hydraulic portions of the vehicle brake system cannot be drawn. Computed or estimated models based on the single measured value involve a risk of error, which necessarily worsens the quality of control in such vehicle brake systems.